JP3770980B2 - Phenolic compound and electrophotographic photoreceptor containing the same - Google Patents

Description

（式中、Ｒ _１ 、Ｒ _４ 、Ｒ _１ ’、Ｒ _４ ’は水素原子：メチル基、エチル基、プロピル基、ｎ−ブチル基、ｔ−ブチル基等のアルキル基：フッ素原子、塩素原子等のハロゲン原子等により置換された置換アルキル基：メトキシカルボニル基、エトキシカルボニル基等のアルコキシカルボニル基：フッ素原子、塩素原子等のハロゲン原子等により置換された置換アルコキシカルボニル基：メトキシ基、エトキシ基等のアルコキシ基：フッ素原子、塩素原子等のハロゲン原子等により置換された置換アルコキシ基：ニトロ基：シアノ基：フッ素原子、塩素原子等のハロゲン原子、フェニル基、ナフチル基等のアリール基：フッ素原子及び塩素原子等のハロゲン原子、又はメチル基、エチル基、プロピル基、ｎ−ブチル基及びｔ−ブチル基等のアルキル基、又はフッ素原子及び塩素原子等のハロゲン原子等により置換された置換アルキル基、又はメトキシ基、エトキシ基等のアルコキシ基等により置換された置換アリール基を表す。式中、Ｒ _２ 、Ｒ _３ 、Ｒ _２ ’、Ｒ _３ ’は、メチル基、エチル基、プロピル基、ｎ−ブチル基、ｔ−ブチル基等のアルキル基：フッ素原子、塩素原子等のハロゲン原子等により置換された置換アルキル基：メトキシカルボニル基、エトキシカルボニル基等のアルコキシカルボニル基：フッ素原子、塩素原子等のハロゲン原子等により置換された置換アルコキシカルボニル基：メトキシ基、エトキシ基等のアルコキシ基：フッ素原子、塩素原子等のハロゲン原子等により置換された置換アルコキシ基：ニトロ基：シアノ基：フッ素原子、塩素原子等のハロゲン原子、フェニル基、ナフチル基等のアリール基：フッ素原子及び塩素原子等のハロゲン原子、又はメチル基、エチル基、プロピル基、ｎ−ブチル基及びｔ−ブチル基等のアルキル基、又はフッ素原子及び塩素原子等のハロゲン原子等により置換された置換アルキル基、又はメトキシ基、エトキシ基等のアルコキシ基等により置換された置換アリール基を表す。ｘは０〜５の整数を表わす。）
【００１２】
本発明によれば、第二に上記第一の感光体において、感光層が電荷発生物質及び電荷輸送物質を含有する単一層であることを特徴とする電子写真感光体が提供される。
【００１３】
本発明によれば、第三に上記第一の感光体において、感光層が電荷発生物質を含有する電荷発生層と電荷輸送物質を含有する電荷輸送層との積層からなり、該電荷輸送層に前記一般式（１）で示されるフェノール系化合物の少なくとも１種を含有させたことを特徴とする電子写真感光体が提供される。
【００１４】
本発明によれば、第四に上記第三の感光体において、電荷輸送物質が正孔輸送物質よりなることを特徴とする電子写真感光体が提供される。
【００１５】
本発明によれば、第五に上記第四の感光体において、正孔輸送物質が下記一般式（２）で示される化合物であることを特徴とする電子写真感光体が提供される。
【化４】

【００１６】
本発明によれば、第六に上記第三の感光体において、電荷輸送物質が電子輸送物質よりなることを特徴とする電子写真感光体が提供される。
【００１７】
本発明によれば、第七に上記第三の感光体において、電荷発生物質の一部又は全部にフタロシアニン系化合物を用いたことを特徴とする電子写真感光体が提供される。
【００１８】
【発明の実施の形態】
前記一般式（１）で表わされるフェノール化合物は、例えば以下の方法（表１）により得られる。まず、相当するフェノール化合物を酸化剤の存在化で反応させて中間体を合成する。反応は通常無溶媒か、クロロホルム、ジクロロエタン等のハロゲン系溶媒中で行うことができる。反応温度は０〜１００℃とすることが好ましい。
【００１９】
【表１】

【００２０】
また、共役鎖を有する式（１）の化合物の中間体は、例えばＪ．Ｏｒｇ．Ｃｈｅｍ．、３６．１３３９（１９７１）に示されるように、対応するフェノールから得られる。炭酸銀等の触媒を加えると、良好な収率で目的物が得られる。反応は通常無溶媒か、ベンゼン、トルエン等の芳香族系溶剤、クロロホルム、ジクロロエタン等のハロゲン系溶媒中で行うことができる。反応温度は０〜２００℃で行い、加熱環流することが好ましい。
【００２１】
【表２】

【００２２】
一般式（１）の化合物は、これらの中間体を、ハイドロサルファイト等の触媒の存在下に還元して得られる。また、水酸化ナトリウム等のアルカリを加えると、良好な収率で目的物が得られる。反応は通常無溶媒か、エチレングリコールジメチルエーテル、ジイソプロピルエーテル等のエーテル系溶媒、水、ジクロロメタン、ジクロロエタン、クロロホルム等のハロゲン系溶媒、ベンゼン、トルエン等の芳香族系溶媒中で行うことができる。反応温度は０〜１００℃とすることが好ましい。
【００２３】
【表３】

【００２４】
本発明において用いられるフェノール系化合物の具体例としては、表４に示すものが挙げられるが、これらに限定されるものではない。
【００２５】
【表４−（１）】

【００２６】
【表４−（２）】

【００２７】
本発明の電子写真感光体は、導電性基体上に、一般式（１）で表わされるフェノール系化合物を含有させた感光層を設けたものであり、必要に応じて、導電性基体と感光層との接着性を向上させる等の目的で、導電性基体と感光層との間に下引き層を形成してもよく、また感光体の耐摩耗性などの機械的耐久性を向上させるために、感光層上に保護層を設けてもよい。
感光層に前記一般式（１）で示されるフェノール系化合物を含有させることにより、電子写真感光体において、化学的耐久性及び繰り返し特性の向上が達成される。本発明の電子写真感光体には、感光層が単層からなるいわゆる単層型電子写真感光体、電荷発生層と電荷輸送層との積層からなるいわゆる積層型電子写真感光体のいずれも含まれる。
【００２８】
単層型電子写真感光体の場合、電荷輸送材料、電荷発生材料、及び前記一般式（１）で示されるフェノール系化合物を、適当な溶媒に、必要に応じてバインダ樹脂と共に溶解もしくは分散せしめることにより、感光層塗布液を調製し、この塗布液を導電性基体上に塗布し、乾燥させることにより設けることができる。ここで使用される電荷輸送材料、電荷発生材料、溶媒、バインダ樹脂などは、後述する積層型電子写真感光体において用いられるものがそのまま使用することができる。
【００２９】
このフェノール系化合物の感光層における含有量としては、電荷輸送物質に対して０．１重量％〜５０重量％、好ましくは０．１重量％〜３０重量％である。０．１重量％以下では残留電位の低減、繰り返し特性の向上に対する効果が十分でなく、また５０重量％以上だと電荷輸送層の膜質、及び機械的耐久性が悪く、感度低下を来す。
【００３０】
電荷輸送層に含有させる正孔輸送物質としては、従来公知の正孔輸送物質が使用でき、例えば、分子中にトリフェニルアミン部位を有する化合物、ヒドラゾン化合物、ピラゾリン化合物、トリフェニルメタン化合物、オキサゾール化合物、オキサジアゾール化合物、カルバゾール環を含む化合物、スチリル化合物、ブタジエン化合物、ポリシラン化合物、ポリ−Ｎ−ビニルカルバゾール、ピレン−ホルマリン縮合化合物等のドナー性化合物を単独もしくは複数で使用することができる。中でも前記一般式（２）で示されるトリフェニルアミン化合物は、バインダー樹脂との相溶性が良好である等の理由により、好適に使用することができる。
【００３１】
電荷輸送層に含有させる電子輸送物質としては、従来公知の電子輸送物質が使用でき、例えば、トリニトロフルオレノン、或いは、フルオレニリデンメタン誘導体などのフルオレン系化合物、ジフェノキノンあるいはアントラキノン誘導体などのキノン系化合物、などを挙げることができる。
【００３２】
電荷発生物質としては、可視光を吸収してフリー電荷を発生するものであれば、無機物質及び有機物質のいずれでもよく、例えば、無定形セレン、三方晶系セレン、セレン−砒素合金、セレン−テルル合金、硫化カドミウム、セレン化カドミウム、硫セレン化カドミウム、アモルファスシリコン等の無機物質、或いはビスアゾ系色素、ポリアゾ系色素、トリアリールメタン色素、チアジン系色素、オキサジン系色素、キサンテン系色素、シアニン系色素、スチリル系色素、ピリリウム系色素、キナクリドン系色素、インジゴ系色素、ペリレン系色素、多環キノン系色素、ビスベンズイミダゾール系色素、インダンスロン系色素、スクアリウム系色素、アントラキノン系色素、及びフタロシアニン系色素等の有機物質が挙げられ、なかでも、ｘ型無金属フタロシアニンは、良好な感度を示す等の理由により、好適に使用することができる。
【００３３】
積層型電子写真感光体の場合、電荷輸送層は、電荷輸送物質、及び前記一般式（１）で示されるフェノール系化合物を、適当な溶媒に、必要に応じてバインダ樹脂と共に溶解もしくは分散せしめ、塗布し乾燥させることにより設けることができる。この電荷輸送層における電荷輸送物質とバインダ樹脂との割合は、電荷輸送物質１００重量部に対してバインダ樹脂が０〜４００重量部、特に好ましくは５０〜２００重量部である。電荷輸送層の膜厚としては、５〜５０μｍ、特に好ましくは１０〜３０μｍである。
【００３４】
電荷発生層は、次の方法によって設けることが好ましい。すなわち、電荷発生物質を適当な溶媒に、必要に応じてバインダ樹脂と共に分散させ、この分散液を導電性基体上に塗布し、乾燥させ電荷発生層を形成する。電荷発生物質の分散方法としては、例えば、ボールミル、超音波、ホモミキサー等が挙げられ、また塗布手段としては、ディッピング塗工法、ブレード塗工法、スプレー塗工法等が挙げられる。
【００３５】
前記の電荷発生物質を分散せしめて電荷発生層を形成する場合、層中への分散性を良くするために、その電荷発生物質は２μｍ以下、好ましくは１μｍ以下の粒径のものが好ましい。ただし、上記の粒径があまりに小さいとかえって凝集しやすく、層の抵抗が上昇したり、結晶欠陥が増えて感度及び繰り返し特性が低下したり、或いは微細化する上で限界があるから、粒径の下限を０．０１μｍとするのが好ましい。
【００３６】
電荷発生層における電荷発生物質とバインダ樹脂との割合としては、電荷発生物質１００重量部に対して、バインダ樹脂０〜５００重量部、特に好ましくは０〜３００重量部である。電荷発生層の膜厚としては、好ましくは０．０５〜１０μｍ、特に好ましくは０．１〜５μｍである。
【００３７】
電荷発生層或いは電荷輸送層の分散液或いは溶液を調製する際に使用する溶媒としては、例えば、Ｎ，Ｎ−ジメチルホルムアミド、トルエン、キシレン、モノクロルベンゼン、１，２−ジクロルエタン、１，１，１−トリクロルエタン、ジクロルメタン、１，１，２−トリクロルエタン、トリクロルエチレン、テトラヒドロフラン、メチルエチルケトン、メチルイゾブチルケトン、シクロヘキサノン、酢酸エチル、酢酸ブチル等を挙げることができる。
【００３８】
また、電荷発生層或いは電荷輸送層に用いられるバインダ樹脂としては、例えば、ポリエチレン、ポリビニルブチラール、ポリビニルホルマール、ポリスチレン樹脂、ポリプロピレン、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、エポキシ樹脂、ポリウレタン樹脂、フェノール樹脂、ポリエステル樹脂、アルキッド樹脂、ポリカーボネート樹脂、ポリアミド樹脂、シリコン樹脂、メラミン樹脂等の付加重合型樹脂、重付加型樹脂、重縮合型樹脂、ならびにこれらの樹脂の繰り返し単位のうち２つ以上を含む共重合体樹脂、例えば塩化ビニル−酢酸ビニル共重合体、スチレン−アクリル共重合体、塩化ビニル−酢酸ビニル−無水マレイン酸共重合体等の絶縁性樹脂のほか、ポリ−Ｎ−ビニルカルバゾール等の高分子有機半導体が挙げられる。
【００３９】
導電性基体としては、アルミニウム、ニッケル、銅、チタン、金、ステンレス等の金属板、金属ドラムまたは金属箔、アルミニウム、ニッケル、銅、チタン、金、酸化錫、酸化インジウムなどを蒸着したプラスチックフィルム或いは導電性物質を塗布した紙、プラスチックなどのフィルムまたはドラム等が挙げられる。
【００４０】
下引き層に用いられる材料としては、前記バインダ樹脂として挙げたものの他に、ポリアミド樹脂、ポリビニルアルコール、エチルセルロース、カルボキシメチルセルロース、塩化ビニル−酢酸ビニル共重合体、塩化ビニル−酢酸ビニル−無水マレイン酸共重合体、カゼイン、Ｎ−アルコキシメチルナイロン等に樹脂をそのまま、または酸化スズ、酸化アルミニウム、酸化チタン、酸化ケイ素、或いは酸化インジウムなどを分散させたもの、酸化アルミニウム、酸化亜鉛、酸化チタン、或いは酸化ケイ素などの蒸着膜等が挙げられる。
【００４１】
更にまた、前記保護層に用いられる材料としては、前述の樹脂をそのまま使用するか、または酸化スズや酸化インジウムなどの低抵抗物質を分散させたものが適当である。また、有機プラズマ重合膜も使用でき、その有機プラズマ重合膜は、必要に応じて適宜酸素、ハロゲン、周期律表の第III族、第Ｖ族原子を含んでもよい。
【００４２】
【実施例】
次に実施例を挙げて本発明をさらに具体的に説明するが、本発明はこれらに限定されるものではない。
【００４３】
実施例１
（式（１）で表わされる化合物の合成例１）
２，６−ジ−フェニルフェノール４０ｍｍｏｌ、過マンガン酸カリウム１６０ｍｍｏｌを、クロロホルム（溶剤）３００ｍｌに入れ、３時間加熱環流した。後処理は、不溶部を瀘別後、シリカゲルを用いたカラムクロマトグラフィーにより単離し、粗生成物を得た。これを再結晶し、中間体ジフェノキノン化合物（Ｂ−１）を、収率９６％で得た。（融点２７８℃）
【化３】

続いて、エチレングリコールジメチルエーテル３００ｍｌ中に、（Ｂ−１）６ｍｍｏｌを溶解し、そこへハイドロサルファイト３００ｍｍｏｌ、水酸化ナトリウム８４ｍｍｏｌを水３００ｍｌに溶解させた水溶液を加え、室温で３時間撹拌した。後処理は、反応溶液を、クロロホルムで抽出後水洗し、シリカゲルを用いたカラムクロマトグラフィーにより単離し、粗生成物を得た。これをトルエン（再結晶溶媒）を用いて再結晶し、前記例示化合物Ｎｏ．５の目的物を得た。（融点１８３．０〜１８４．０℃収率８５％）
【００４４】
実施例２〜６
（式（１）で表わされる化合物の合成例２〜６）
出発原料をそれぞれ若干変えた以外は合成例１と同様にして式（１）で表わされる化合物を製造した。表５にこれら化合物の融点、元素分析結果を示す。
【００４５】
【表５】

【００４６】
実施例７
電荷発生物質として下記構造式（Ｐ−１）のトリスアゾ顔料５重量部、ポリビニルブチラール樹脂（エスレックスＢＬＳ：積層化学社製）５重量部、及びＴＨＦ（テトラヒドロフラン）９０重量部をボールミルにて１２時間分散させ、次にテトラヒドロフランを２重量％の分散液濃度になるように加え、再分散させて塗布液を調製した。このように調製した塗布液をＡｌ基板上にドクターブレードにて流延塗布し、乾燥後の膜厚が０．５μｍの電荷発生層を形成した。
次に、ＴＨＦを２０２．５ｇ、ポリカーボネートＺ（帝人化成社製）を２５．０ｇ、シリコンオイル（ＫＦ５０，信越化学社製）の０．１ｗｔ％ＴＨＦ溶液を５．０ｇ秤量し、室温で撹拌して溶解して溶解させ、ＰＣ−Ｚ溶液Ａを調製した。
また、サンプル瓶中に、予め下記構造式（Ｄ−１）の正孔輸送物質を０．７ｇ、表４の例示化合物Ｎｏ．２のフェノール系化合物を９．４×１０^-5ｍｏｌに相当する量採取しておき、先に調製したＰＣ−Ｚ溶液Ａを９．３ｇ加えて室温で撹拌し、電荷輸送層塗布液を調製した。
これを電荷発生層上にドクターブレードにて塗布し乾燥させて膜厚が２０μｍの電荷輸送層を設け、電子写真感光体を得た。
【化４】

【化５】

【００４７】
実施例８
実施例７で使用した例示化合物Ｎｏ．２の代わりに例示化合物Ｎｏ．３を使用すること以外は、実施例７と同様な方法で、電子写真感光体を作製した。
【００４８】
実施例９
実施例７で使用した例示化合物Ｎｏ．２の代わりに例示化合物Ｎｏ．５を使用すること以外は、実施例７と同様な方法で、電子写真感光体を作製した。
【００４９】
実施例１０
実施例７で使用した例示化合物Ｎｏ．２の代わりに例示化合物Ｎｏ．７を使用すること以外は、実施例７と同様な方法で、電子写真感光体を作製した。
【００５０】
比較例１
実施例７で使用した例示化合物Ｎｏ．２を添加しないこと以外は、実施例７と同様な方法で、電子写真感光体を作製した。
【００５１】
（静電特性）
以上のようにして作製した電子写真感光体に、静電複写紙測定装置（川口電機社製ＥＰＡ８１００）を使用して、−１８μＡでコロナ放電を２０秒行って帯電せしめ、続いて２０秒暗減衰させた後の表面電位Ｖ₀（Ｖ）、感光体表面で５μＷ／ｃｍ²となる光量の７８０ｎｍ単色光を照射後、Ｖ₀が１／２になるのに必要な露光量Ｅ_1/2（μＪ／ｃｍ²）を測定した。また、３０秒間光照射した後の表面電位Ｖｒ（Ｖ）とした。その測定結果を表６に示す。
【００５２】
（化学的耐久性試験）
実施例７〜１０、比較例１で作製した電子写真感光体を、ＮＯｘガス（ＮＯ：ＮＯ₂＝４：１）暴露試験器内に、室温で４日間放置した後の静電特性も併せて表６に示す。
【００５３】
【表６】

【００５４】
実施例１１
電荷発生物質としてｘ型無金属フタロシアニンを使用すること以外は、実施例７と同様な方法で、電子写真感光体を作製した。
次に、下記構造式（Ａ−１）の電荷輸送物質８重量部、前記の例示化合物Ｎｏ．２のフェノール系化合物１重量部、ポリカーボネートＺ（帝人化成社製）１２重量部、シリコンオイル（ＫＦ５０，信越化学社製）０．０２重量部をテトラヒドロフラン９０重量部に溶解し、これを電荷発生層上にドクターブレードにて塗布し、乾燥させて膜厚が２０μｍの電荷輸送層を設け、電子写真感光体を作製した。
【化６】

【００５５】
実施例１２
実施例１１において、例示化合物Ｎｏ．２を例示化合物Ｎｏ．３に代えた以外は、実施例５と同様にして電子写真感光体を作製した。
【００５６】
比較例２
実施例１１で使用した例示化合物Ｎｏ．２を添加しないこと以外は、実施例１１と同様な方法で、電子写真感光体を作製した。
【００５７】
（静電特性）
以上のようにして作製した電子写真感光体に、川口電機社製の静電複写紙試験装置（ＥＰＡ８２００）を用い、＋５．３ＫＶでコロナ放電を２０秒行って帯電せしめ、続いて２０秒暗減衰させた後の表面電位Ｖ₀（Ｖ）、感光体表面で５μＷ／ｃｍ²となる光量の７８０ｎｍ単色光を照射後、Ｖ₀が１／２になるのに必要な露光量Ｅ_1/2（μＪ／ｃｍ²）を測定した。また、３０秒間光照射した後の表面電位Ｖｒ（Ｖ）とした。その測定結果を表７に示す。
【００５８】
（化学的耐久性試験）
実施例１１、実施例１２、比較例２で作製した電子写真感光体を、ＮＯｘガス（ＮＯ：ＮＯ₂＝４：１）暴露試験器内に、室温で４日間放置した後の静電特性を表６に示す。
【００５９】
【表７】

【００６０】
実施例１３
ｘ型無金属フタロシアニン１ｇ、ポリカーボネートＺ（ＰＣ−Ｚ）の１０ｗｔ％ＴＨＦ溶液１０ｇ、ＴＨＦ９ｇをボールミル中で一晩ミリングした。更にＰＣ−Ｚの２０ｗｔ％ＴＨＦ溶液２０ｇを加え、一晩ミリングした（これを１０％分散液とする）。また、サンプル瓶中に、前記の正孔移動物質（Ｄ−１）０．４５ｇ、表４の例示化合物Ｎｏ．２を６．０×１０^-5ｍｏｌに相当する量採取しておき、先に調製した１０％分散液を１．２ｇ、シリコンオイル（ＫＦ５０，信越化学社製）の１ｗｔ％ＴＨＦ溶液を０．１５ｇ、ＴＨＦを１．０３ｇ、ＰＣ−Ｚの１５ｗｔ％ＴＨＦ溶液を４．７ｇを秤量し、室温で撹拌して電荷輸送層塗布液を調製した。
これをＡｌ基板上にドクターブレードにて塗布し、乾燥させて膜厚が２０μｍの電荷輸送層を設け、単層型電子写真感光体を作製した。
【００６１】
実施例１４
実施例１３で使用した例示化合物Ｎｏ．２の代わりに例示化合物Ｎｏ．３を使用すること以外は、実施例１３と同様な方法で、電子写真感光体を作製した。
【００６２】
実施例１５
実施例１３で使用した例示化合物Ｎｏ．２の代わりに例示化合物Ｎｏ．５を使用すること以外は、実施例１３と同様な方法で、電子写真感光体を作製した。
【００６３】
実施例１３で使用した例示化合物Ｎｏ．２の代わりにを例示化合物Ｎｏ．７を使用する以外は、実施例１４と同様な方法で、電子写真感光体を作製した。
【００６４】
比較例３
実施例１３で使用した例示化合物Ｎｏ．２を添加しないこと以外は、実施例１３と同様な方法で、電子写真感光体を作製した。
【００６５】
（静電特性）
以上のようにして作製した電子写真感光体に、静電複写紙測定装置（川口電機社製ＥＰＡ８１００）を用い、−１８μＡでコロナ放電を２０秒行って帯電せしめ、続いて２０秒暗減衰させた後の表面電位Ｖ₀（Ｖ）、感光体表面で５μＷ／ｃｍ²となる光量の７８０ｎｍ単色光を照射後、Ｖ₀が１／２になるのに必要な露光量Ｅ_1/2（μＪ／ｃｍ²）を測定した。また、３０秒間光照射した後の表面電位Ｖｒ（Ｖ）とした。その測定結果を表８に示す。
【００６６】
（化学的耐久性試験）
実施例１３、実施例１４、実施例１５、実施例１６、比較例３で作製した電子写真感光体を、ＮＯｘガス（ＮＯ：ＮＯ₂＝４：１）暴露試験器内に、室温で４日間放置した後の静電特性も併せて表８に示す。
【００６７】
【表８】

【００６８】
【発明の効果】
請求項１の発明によれば、良好な酸化防止効果を有する新規酸化防止剤が提供される。
請求項２の発明によれば、電子写真感光体の感光層にフェノール系化合物を含有させることにより、化学的耐久性を向上させることができる。
請求項３の発明によれば、単層型電子写真感光体の感光層にフェノール系化合物を含有させることにより、化学的耐久性を向上させることができる。
請求項４の発明によれば、電荷発生層と電荷輸送層を有する積層型電子写真感光体において、電荷輸送層中にフェノール系化合物を含有させることにより、化学的耐久性を向上させることができる。
請求項５の発明によれば、電荷輸送層に、正孔輸送物質と共にフェノール系化合物を含有させることにより、化学的耐久性を向上させることができる。
請求項６の発明によれば、特定の正孔輸送物質を用いることにより、化学的耐久性をさらに向上させることができる。
請求項７の発明によれば、電荷輸送層に、電荷輸送物質と共にフェノール系化合物を含有させることにより、化学的耐久性を向上させることができる。
請求項８の発明によれば、電荷発生物質として、フタロシアニン系化合物を使用することで、感度を向上させる効果がある。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member used for a copying machine, a printer and the like using an electrophotographic process.
[0002]
[Prior art]
Conventionally, as electrophotographic photoreceptors, inorganic electrophotographic photoreceptors composed of inorganic materials such as selenium, selenium-tellurium alloy, arsenic-selenium and the like have been used in many copying machines. However, these inorganic materials for electrophotographic photoreceptors have problems in the environment at the time of producing the photoreceptor, and are used in an amorphous state. For example, they are easily crystallized due to heat, dirt, etc. Is troublesome. Moreover, since it is necessary to perform vacuum deposition to a film thickness of several tens of μm, there are disadvantages such as an increase in cost.
[0003]
In order to improve these drawbacks, electrophotographic photosensitive members using organic materials have been actively developed and put into practical use. As this advantage, it is inexpensive and suitable for mass production. On the other hand, since it is an organic material, deterioration of the material due to repeated use cannot be avoided. In addition, the surface layer of the photoreceptor, that is, the layer farthest from the substrate, is directly subjected to mechanical and chemical external forces such as corona charging, toner development, transfer to paper, and cleaning treatment. Sex is also required.
[0004]
The term “mechanical external force” as used herein specifically refers to the occurrence of surface wear or scratches due to rubbing. In order to solve this problem, a lubricant is contained in the surface layer or the protective layer of the photoconductor (Japanese Patent Laid-Open Nos. 52-117134, 63-61256, etc.) to reduce the friction coefficient of the photoconductor. Is known to be effective. Further, as chemical deterioration, deterioration due to light irradiation, oxidation of a photoreceptor material by ozone or nitrogen oxide (NOx) generated by corona discharge, and the like are considered. In particular, it is known to add a specific antioxidant for the purpose of preventing the oxidation of the photosensitive material (JP-A-4-184455, JP-A-6-17538, JP-A-3-188456, etc.).
However, no satisfactory results (characteristics) have been obtained so far, and further improvements have been desired.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide an organic material that is particularly excellent in an antioxidant effect. Another object of the present invention is to provide an electrophotographic photosensitive member which has less fatigue in repeated use and is excellent in charging potential stability. Still another object of the present invention is to provide an electrophotographic photoreceptor excellent in environmental resistance (reaction gas resistance).
[0006]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found that a phenolic compound having a specific structure has an excellent antioxidant effect.
[0007]
In addition, conventionally, an electrophotographic photosensitive member in which at least a photosensitive layer is provided on a conductive substrate is considered to be deteriorated by repeated use or by a reactive gas (ozone, NOx). However, as a result of diligent investigation on this point, the present inventors have found that in an electrophotographic photoreceptor in which at least a photosensitive layer is provided on a conductive substrate, By containing at least one phenolic compound having the above specific structure in the photosensitive layer, it is possible to inactivate the reactive gas that has entered the photoreceptor, thereby reducing chargeability and sensitivity. It has been found that it is possible to provide an electrophotographic photosensitive member that is excellent in repeated durability and chemical durability.
[0008]
Further, in the electrophotographic photosensitive member in which the photosensitive layer is provided with a charge generation layer made of a charge generation material and a charge transport layer containing a charge transport material in this order, a hole is formed in the charge transport layer. In the negatively charged electrophotographic photoreceptor containing a transport material and the positively charged electrophotographic photoreceptor containing an electron transport material in the charge transport layer, the phenolic compound represented by the general formula (1) in the charge transport layer is also used. It has been found that by containing at least one compound, it is possible to provide an electrophotographic photoreceptor excellent in repeated durability and chemical durability by preventing reduction in chargeability and sensitivity.
[0009]
Furthermore, even in a single-layer type electrophotographic photosensitive member having a single layer containing a charge generating substance and a charge transporting substance, the photosensitive layer is charged by containing a phenol compound having the specific structure in the photosensitive layer. It has been found that it is possible to provide an electrophotographic photosensitive member that is excellent in repeated durability and chemical durability while preventing deterioration of properties and sensitivity.
[0011]
  According to the present invention,PrimarilyIn an electrophotographic photoreceptor in which at least a photosensitive layer is provided on a conductive substrate, in the photosensitive layer,followingAn electrophotographic photoreceptor characterized in that it contains at least one phenolic compound represented by the general formula (1) is provided.
[Chemical Formula 3]

(Wherein R ₁ , R ₄ , R ₁ ', R ₄ 'Represents a hydrogen atom: an alkyl group such as a methyl group, an ethyl group, a propyl group, an n-butyl group or a t-butyl group: a substituted alkyl group substituted with a halogen atom such as a fluorine atom or a chlorine atom: a methoxycarbonyl group, Alkoxycarbonyl groups such as ethoxycarbonyl groups: Substituted alkoxycarbonyl groups substituted by halogen atoms such as fluorine atoms and chlorine atoms: Alkoxy groups such as methoxy groups and ethoxy groups: Substituted by halogen atoms such as fluorine atoms and chlorine atoms Substituted alkoxy group: nitro group: cyano group: halogen atom such as fluorine atom and chlorine atom, aryl group such as phenyl group and naphthyl group: halogen atom such as fluorine atom and chlorine atom, or methyl group, ethyl group, propyl Groups, alkyl groups such as n-butyl group and t-butyl group, or fluorine atom and chlorine atom It represents a substituted alkyl group substituted by a halogen atom or the like, or a substituted aryl group substituted by an alkoxy group such as a methoxy group or an ethoxy group. Where R ₂ , R ₃ , R ₂ ', R ₃ 'Represents an alkyl group such as a methyl group, an ethyl group, a propyl group, an n-butyl group or a t-butyl group: a substituted alkyl group substituted with a halogen atom such as a fluorine atom or a chlorine atom: a methoxycarbonyl group or an ethoxycarbonyl group Alkoxycarbonyl groups such as groups: Substituted alkoxycarbonyl groups substituted by halogen atoms such as fluorine atoms and chlorine atoms: Alkoxy groups such as methoxy groups and ethoxy groups: Substituted by halogen atoms such as fluorine atoms and chlorine atoms Substituted alkoxy group: nitro group: cyano group: halogen atom such as fluorine atom and chlorine atom, aryl group such as phenyl group and naphthyl group: halogen atom such as fluorine atom and chlorine atom, or methyl group, ethyl group, propyl group, Alkyl groups such as n-butyl and t-butyl groups, or halogens such as fluorine and chlorine atoms A substituted alkyl group substituted by an atom or the like, or a substituted aryl group substituted by an alkoxy group such as a methoxy group or an ethoxy group is represented. x represents an integer of 0 to 5. )
[0012]
  According to the present invention,Second, the firstThe electrophotographic photosensitive member is characterized in that the photosensitive layer is a single layer containing a charge generating substance and a charge transporting substance.
[0013]
  According to the present invention,Third, the firstIn this photoreceptor, the photosensitive layer comprises a laminate of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material, and the phenolic compound represented by the general formula (1) in the charge transport layer There is provided an electrophotographic photosensitive member containing at least one of the above.
[0014]
  According to the present invention,Fourth, third aboveAn electrophotographic photoreceptor is provided in which the charge transport material is a hole transport material.
[0015]
  According to the present invention,Fifth, fourth aboveAn electrophotographic photoreceptor is provided in which the hole transport material is a compound represented by the following general formula (2).
[Formula 4]

[0016]
  According to the present invention,Sixth, third aboveAn electrophotographic photosensitive member is provided in which the charge transport material is an electron transport material.
[0017]
  According to the present invention,Seventh to third aboveAn electrophotographic photosensitive member is provided in which a phthalocyanine compound is used for a part or all of the charge generating material.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The phenol compound represented by the general formula (1) can be obtained, for example, by the following method (Table 1). First, an intermediate is synthesized by reacting a corresponding phenol compound in the presence of an oxidizing agent. The reaction can be usually carried out in the absence of a solvent or in a halogen solvent such as chloroform or dichloroethane. The reaction temperature is preferably 0 to 100 ° C.
[0019]
[Table 1]

[0020]
Intermediates of the compound of the formula (1) having a conjugated chain are, for example, J. Org. Chem. ,36. 1339 (1971), obtained from the corresponding phenol. When a catalyst such as silver carbonate is added, the desired product is obtained in a good yield. The reaction can be usually carried out in the absence of a solvent, an aromatic solvent such as benzene or toluene, or a halogen solvent such as chloroform or dichloroethane. The reaction temperature is preferably 0 to 200 ° C. and heated to reflux.
[0021]
[Table 2]

[0022]
The compound of the general formula (1) is obtained by reducing these intermediates in the presence of a catalyst such as hydrosulfite. Further, when an alkali such as sodium hydroxide is added, the desired product can be obtained in a good yield. The reaction can be usually carried out in the absence of a solvent, an ether solvent such as ethylene glycol dimethyl ether or diisopropyl ether, a halogen solvent such as water, dichloromethane, dichloroethane or chloroform, or an aromatic solvent such as benzene or toluene. The reaction temperature is preferably 0 to 100 ° C.
[0023]
[Table 3]

[0024]
Specific examples of the phenolic compound used in the present invention include those shown in Table 4, but are not limited thereto.
[0025]
[Table 4- (1)]

[0026]
[Table 4- (2)]

[0027]
The electrophotographic photosensitive member of the present invention is obtained by providing a photosensitive layer containing a phenolic compound represented by the general formula (1) on a conductive substrate. If necessary, the conductive substrate and the photosensitive layer are provided. An undercoat layer may be formed between the conductive substrate and the photosensitive layer for the purpose of improving the adhesion to the photosensitive member, and in order to improve the mechanical durability such as the abrasion resistance of the photosensitive member. A protective layer may be provided on the photosensitive layer.
By including the phenolic compound represented by the general formula (1) in the photosensitive layer, the chemical durability and the repetition characteristics are improved in the electrophotographic photosensitive member. The electrophotographic photosensitive member of the present invention includes both a so-called single layer type electrophotographic photosensitive member in which the photosensitive layer is a single layer and a so-called multilayer type electrophotographic photosensitive member in which the charge generation layer and the charge transport layer are laminated. .
[0028]
In the case of a single layer type electrophotographic photoreceptor, the charge transport material, the charge generation material, and the phenol compound represented by the general formula (1) are dissolved or dispersed in a suitable solvent together with a binder resin as necessary. By preparing a photosensitive layer coating solution, the coating solution can be applied on a conductive substrate and dried. As the charge transporting material, charge generating material, solvent, binder resin and the like used here, those used in a laminated electrophotographic photosensitive member described later can be used as they are.
[0029]
The content of the phenolic compound in the photosensitive layer is 0.1% to 50% by weight, preferably 0.1% to 30% by weight, based on the charge transport material. If it is 0.1% by weight or less, the effect of reducing the residual potential and improving the repetitive characteristics is not sufficient, and if it is 50% by weight or more, the film quality and mechanical durability of the charge transport layer are poor and the sensitivity is lowered.
[0030]
As the hole transport material to be contained in the charge transport layer, conventionally known hole transport materials can be used. For example, compounds having a triphenylamine moiety in the molecule, hydrazone compounds, pyrazoline compounds, triphenylmethane compounds, oxazole compounds , An oxadiazole compound, a compound containing a carbazole ring, a styryl compound, a butadiene compound, a polysilane compound, a poly-N-vinylcarbazole, a pyrene-formalin condensed compound, and the like can be used alone or in combination. Among these, the triphenylamine compound represented by the general formula (2) can be suitably used for reasons such as good compatibility with the binder resin.
[0031]
As the electron transport material to be contained in the charge transport layer, conventionally known electron transport materials can be used, for example, trinitrofluorenone, fluorene compounds such as fluorenylidenemethane derivatives, quinone compounds such as diphenoquinone or anthraquinone derivatives. , Etc.
[0032]
As the charge generation material, any material can be used as long as it absorbs visible light and generates free charge. For example, amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium- Tellurium alloys, cadmium sulfide, cadmium selenide, cadmium sulfide selenide, amorphous silicon and other inorganic materials, or bisazo dyes, polyazo dyes, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine dyes Dyes, styryl dyes, pyrylium dyes, quinacridone dyes, indigo dyes, perylene dyes, polycyclic quinone dyes, bisbenzimidazole dyes, indanthrone dyes, squalium dyes, anthraquinone dyes, and phthalocyanines Organic substances such as pigments, among which x Metal-free phthalocyanine, because, for example exhibit good sensitivity, can be suitably used.
[0033]
In the case of a multilayer electrophotographic photoreceptor, the charge transport layer is prepared by dissolving or dispersing the charge transport material and the phenol compound represented by the general formula (1) in an appropriate solvent together with a binder resin as necessary. It can be provided by applying and drying. The ratio of the charge transport material and the binder resin in the charge transport layer is 0 to 400 parts by weight, particularly preferably 50 to 200 parts by weight, based on 100 parts by weight of the charge transport material. The thickness of the charge transport layer is 5 to 50 μm, particularly preferably 10 to 30 μm.
[0034]
The charge generation layer is preferably provided by the following method. That is, a charge generation material is dispersed in a suitable solvent together with a binder resin as necessary, and this dispersion is applied onto a conductive substrate and dried to form a charge generation layer. Examples of the method for dispersing the charge generating substance include a ball mill, an ultrasonic wave, and a homomixer. Examples of the application means include a dipping coating method, a blade coating method, and a spray coating method.
[0035]
When the charge generation material is dispersed to form a charge generation layer, the charge generation material preferably has a particle size of 2 μm or less, preferably 1 μm or less in order to improve dispersibility in the layer. However, if the above particle size is too small, it tends to agglomerate, the resistance of the layer increases, the crystal defects increase, the sensitivity and repeatability decrease, or there is a limit to miniaturization, the particle size The lower limit is preferably 0.01 μm.
[0036]
The ratio of the charge generation material to the binder resin in the charge generation layer is 0 to 500 parts by weight, particularly preferably 0 to 300 parts by weight, based on 100 parts by weight of the charge generation material. The film thickness of the charge generation layer is preferably 0.05 to 10 μm, particularly preferably 0.1 to 5 μm.
[0037]
Examples of the solvent used when preparing the dispersion or solution of the charge generation layer or charge transport layer include N, N-dimethylformamide, toluene, xylene, monochlorobenzene, 1,2-dichloroethane, 1,1,1. -Trichloroethane, dichloromethane, 1,1,2-trichloroethane, trichloroethylene, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate and the like.
[0038]
Examples of the binder resin used for the charge generation layer or the charge transport layer include polyethylene, polyvinyl butyral, polyvinyl formal, polystyrene resin, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, and polyurethane. 2 of resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, polyamide resin, silicone resin, melamine resin and other addition polymerization resins, polyaddition resin, polycondensation resin, and repeating units of these resins Copolymer resins containing the above, for example, insulating resins such as vinyl chloride-vinyl acetate copolymer, styrene-acrylic copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, and poly-N-vinyl High molecular organics such as carbazole Conductor and the like.
[0039]
As the conductive substrate, a metal plate such as aluminum, nickel, copper, titanium, gold, and stainless steel, a metal drum or a metal foil, a plastic film on which aluminum, nickel, copper, titanium, gold, tin oxide, indium oxide, etc. are deposited or Examples thereof include paper coated with a conductive material, a film such as plastic, or a drum.
[0040]
As materials used for the undercoat layer, in addition to those mentioned as the binder resin, polyamide resin, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer Polymer, casein, N-alkoxymethyl nylon, etc. with resin as it is or with tin oxide, aluminum oxide, titanium oxide, silicon oxide, or indium oxide dispersed, aluminum oxide, zinc oxide, titanium oxide, or oxidation For example, a deposited film of silicon or the like.
[0041]
Furthermore, as the material used for the protective layer, the above-described resin is used as it is, or a material in which a low resistance substance such as tin oxide or indium oxide is dispersed is suitable. An organic plasma polymerized film can also be used, and the organic plasma polymerized film may contain oxygen, halogen, and group III and group V atoms of the periodic table as necessary.
[0042]
【Example】
EXAMPLES Next, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to these.
[0043]
Example 1
(Synthesis Example 1 of the compound represented by the formula (1))
40 mmol of 2,6-di-phenylphenol and 160 mmol of potassium permanganate were placed in 300 ml of chloroform (solvent) and heated to reflux for 3 hours. In the post-treatment, the insoluble part was filtered off and then isolated by column chromatography using silica gel to obtain a crude product. This was recrystallized to obtain an intermediate diphenoquinone compound (B-1) with a yield of 96%. (Melting point 278 ° C)
[Chemical Formula 3]

Subsequently, 6 mmol of (B-1) was dissolved in 300 ml of ethylene glycol dimethyl ether, and an aqueous solution in which 300 mmol of hydrosulfite and 84 mmol of sodium hydroxide were dissolved in 300 ml of water was added thereto, followed by stirring at room temperature for 3 hours. In the post-treatment, the reaction solution was extracted with chloroform, washed with water, and isolated by column chromatography using silica gel to obtain a crude product. This was recrystallized using toluene (recrystallization solvent). 5 objects were obtained. (Melting point: 183.0-184.0 ° C., 85% yield)
[0044]
Examples 2-6
(Synthesis Examples 2 to 6 of the compound represented by the formula (1))
A compound represented by the formula (1) was produced in the same manner as in Synthesis Example 1 except that the starting materials were slightly changed. Table 5 shows melting points and elemental analysis results of these compounds.
[0045]
[Table 5]

[0046]
Example 7
As a charge generating substance, 5 parts by weight of a trisazo pigment of the following structural formula (P-1), 5 parts by weight of a polyvinyl butyral resin (Eslex BLS: manufactured by Laminate Chemical Co., Ltd.), and 90 parts by weight of THF (tetrahydrofuran) for 12 hours by a ball mill Next, tetrahydrofuran was added to a dispersion concentration of 2% by weight and redispersed to prepare a coating solution. The coating solution thus prepared was cast applied onto an Al substrate with a doctor blade to form a charge generation layer having a thickness of 0.5 μm after drying.
Next, 202.5 g of THF, 25.0 g of polycarbonate Z (manufactured by Teijin Chemicals Ltd.), and 5.0 g of a 0.1 wt% THF solution of silicon oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) are weighed and stirred at room temperature. And dissolved to prepare a PC-Z solution A.
In addition, 0.7 g of the hole transport material represented by the following structural formula (D-1) was previously contained in the sample bottle, and Exemplified Compound Nos. 2 phenolic compounds of 9.4 × 10^-FiveAn amount corresponding to mol was collected, 9.3 g of the previously prepared PC-Z solution A was added, and the mixture was stirred at room temperature to prepare a charge transport layer coating solution.
This was applied onto the charge generation layer with a doctor blade and dried to provide a charge transport layer having a thickness of 20 μm, thereby obtaining an electrophotographic photoreceptor.
[Formula 4]

[Chemical formula 5]

[0047]
Example 8
Exemplified Compound No. used in Example 7 In place of Ex. An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that No. 3 was used.
[0048]
Example 9
Exemplified Compound No. used in Example 7 In place of Ex. An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that No. 5 was used.
[0049]
Example 10
Exemplified Compound No. used in Example 7 In place of Ex. An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that No. 7 was used.
[0050]
Comparative Example 1
Exemplified Compound No. used in Example 7 An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that 2 was not added.
[0051]
(Electrostatic characteristics)
The electrophotographic photosensitive member produced as described above was charged by using an electrostatic copying paper measuring device (EPA8100 manufactured by Kawaguchi Electric Co., Ltd.) at −18 μA for 20 seconds, followed by dark attenuation for 20 seconds. Surface potential V after₀(V) 5 μW / cm on the photoreceptor surface²After irradiating 780 nm monochromatic light with a light quantity of₀Exposure E required to halve_1/2(ΜJ / cm²) Was measured. Further, the surface potential Vr (V) after light irradiation for 30 seconds was used. The measurement results are shown in Table 6.
[0052]
(Chemical durability test)
The electrophotographic photoreceptors produced in Examples 7 to 10 and Comparative Example 1 were prepared using NOx gas (NO: NO₂= 4: 1) Table 6 also shows electrostatic characteristics after being left in an exposure tester at room temperature for 4 days.
[0053]
[Table 6]

[0054]
Example 11
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that x-type metal-free phthalocyanine was used as the charge generation material.
Next, 8 parts by weight of the charge transport material of the following structural formula (A-1), the exemplified compound No. 1 part by weight of phenolic compound 2, 12 parts by weight of polycarbonate Z (manufactured by Teijin Chemicals) and 0.02 part by weight of silicon oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) are dissolved in 90 parts by weight of tetrahydrofuran, and this is dissolved in a charge generation layer. An electrophotographic photosensitive member was prepared by applying a charge transport layer having a film thickness of 20 μm to the surface by applying with a doctor blade and drying.
[Chemical 6]

[0055]
Example 12
In Example 11, Exemplified Compound No. 2 is exemplified Compound No. An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that it was replaced with 3.
[0056]
Comparative Example 2
Exemplified Compound No. used in Example 11 An electrophotographic photosensitive member was produced in the same manner as in Example 11 except that 2 was not added.
[0057]
(Electrostatic characteristics)
The electrophotographic photosensitive member produced as described above was charged using a corona discharge at +5.3 KV for 20 seconds using an electrostatic copying paper test apparatus (EPA8200) manufactured by Kawaguchi Electric Co., and then darkened for 20 seconds. Surface potential V after₀(V) 5 μW / cm on the photoreceptor surface²After irradiating 780 nm monochromatic light with a light quantity of₀Exposure E required to halve_1/2(ΜJ / cm²) Was measured. Further, the surface potential Vr (V) after light irradiation for 30 seconds was used. The measurement results are shown in Table 7.
[0058]
(Chemical durability test)
The electrophotographic photoreceptors produced in Example 11, Example 12, and Comparative Example 2 were treated with NOx gas (NO: NO₂= 4: 1) Table 6 shows the electrostatic characteristics after being left in an exposure tester at room temperature for 4 days.
[0059]
[Table 7]

[0060]
Example 13
1 g of x-type metal-free phthalocyanine, 10 g of a 10 wt% THF solution of polycarbonate Z (PC-Z), and 9 g of THF were milled overnight in a ball mill. Further, 20 g of a 20 wt% THF solution of PC-Z was added and milled overnight (this was taken as a 10% dispersion). In the sample bottle, 0.45 g of the above-described hole transfer substance (D-1), Exemplified Compound No. 2 is 6.0 × 10^-FiveAn amount corresponding to mol was collected, 1.2 g of the previously prepared 10% dispersion, 0.15 g of 1 wt% THF solution of silicon oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.), 1.03 g of THF, PC 4.7 g of a 15 wt% THF solution of -Z was weighed and stirred at room temperature to prepare a charge transport layer coating solution.
This was coated on an Al substrate with a doctor blade and dried to provide a charge transport layer having a film thickness of 20 μm to produce a single layer type electrophotographic photosensitive member.
[0061]
Example 14
Exemplified Compound No. used in Example 13 In place of Ex. An electrophotographic photosensitive member was produced in the same manner as in Example 13 except that No. 3 was used.
[0062]
Example 15
Exemplified Compound No. used in Example 13 In place of Ex. An electrophotographic photosensitive member was produced in the same manner as in Example 13 except that No. 5 was used.
[0063]
Exemplified Compound No. used in Example 13 Instead of 2, Exemplified Compound No. An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that 7 was used.
[0064]
Comparative Example 3
Exemplified Compound No. used in Example 13 An electrophotographic photosensitive member was produced in the same manner as in Example 13 except that 2 was not added.
[0065]
(Electrostatic characteristics)
The electrophotographic photosensitive member produced as described above was charged using a corona discharge at −18 μA for 20 seconds using an electrostatic copying paper measuring apparatus (EPA8100 manufactured by Kawaguchi Electric Co., Ltd.), and then dark-attenuated for 20 seconds. Later surface potential V₀(V) 5 μW / cm on the photoreceptor surface²After irradiating 780 nm monochromatic light with a light quantity of₀Exposure E required to halve_1/2(ΜJ / cm²) Was measured. Further, the surface potential Vr (V) after light irradiation for 30 seconds was used. The measurement results are shown in Table 8.
[0066]
(Chemical durability test)
The electrophotographic photoreceptors produced in Example 13, Example 14, Example 15, Example 16, and Comparative Example 3 were treated with NOx gas (NO: NO₂= 4: 1) Table 8 also shows electrostatic characteristics after being left in an exposure tester at room temperature for 4 days.
[0067]
[Table 8]

[0068]
【The invention's effect】
According to invention of Claim 1, the novel antioxidant which has a favorable antioxidant effect is provided.
According to invention of Claim 2, chemical durability can be improved by making a photosensitive layer of an electrophotographic photoreceptor contain a phenol type compound.
According to invention of Claim 3, chemical durability can be improved by making a photosensitive layer of a single layer type electrophotographic photosensitive member contain a phenol type compound.
According to the invention of claim 4, in the multilayer electrophotographic photosensitive member having a charge generation layer and a charge transport layer, chemical durability can be improved by incorporating a phenol compound in the charge transport layer. .
According to the fifth aspect of the present invention, chemical durability can be improved by allowing the charge transport layer to contain the phenolic compound together with the hole transport material.
According to the invention of claim 6, chemical durability can be further improved by using a specific hole transport material.
According to invention of Claim 7, chemical durability can be improved by making a charge transport layer contain a phenol type compound with a charge transport material.
According to the eighth aspect of the present invention, the use of a phthalocyanine compound as the charge generating substance has an effect of improving sensitivity.

Claims (5)

On a conductive substrate, an electrophotographic photosensitive member comprising a charge transport layer containing a charge transport material and the charge generating layer containing at least a charge generating material, on the charge transport layer, by the following general formula (1) An electrophotographic photosensitive member comprising at least one of the phenolic compounds shown , and further having a thickness of the charge transport layer of 20 to 50 μm .

(Wherein R ₁ , R ₄ , R ₁ ′ and R ₄ ′ are a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkoxycarbonyl group, a nitro group, a cyano group, Represents a group, a halogen atom, a substituted or unsubstituted aryl group, wherein R ₂ , R ₃ , R ₂ ′ and R ₃ ′ are substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups, substituted Or an unsubstituted alkoxycarbonyl group, a nitro group, a cyano group, a halogen atom, a substituted or unsubstituted aryl group, and x represents an integer of 0 to 5.) The electrophotographic photosensitive member according to claim 1, wherein the charge transport material comprises a hole transport material. The electrophotographic photoreceptor according to claim 2, wherein the hole transport material is a compound represented by the following general formula (2).

The electrophotographic photosensitive member according to claim 1, wherein the charge transport material comprises an electron transport material. 2. The electrophotographic photosensitive member according to claim 1, wherein a phthalocyanine compound is used for a part or all of the charge generation material.